Brake truing device



APril 1935. A. L. MILLER ET AL 1,996,252

BRAKE TRUING DEVICE Filed June. 20, 1932 2 Sheets-Sheet 2 INVENTOR.

in. vm LJWLLER. A fiusssu H-NILL ER.

ATTORNEYS Patented 2, 1935 I I 1,996.25: IBBAKEYTRUINIGT-DEYICE ,Alvin.Il. Miller andRussell- 1 1 Miller," I a y 1 1!-' J'Application Je s-a, 1932', Serial No. 618,115, I I I m c g This invention has to do with a truing device for vehicle brakes, and'it is concerned particularly with brakes such as are used in auto- ,motive vehicles wh'ere brake lining or frictionv material is employed. IThis a'pp'lication isthe continuation in part" *of application #300,168,

filediAugusti .17; 1928; i Brake liningswhich are largely in use -today are composed of very hard material molded or otherwise: formed asdistinguished: from woven brake. lining material. ,In order toj'have acornect brake adjustment and a:nicety'of surface to. surface fltbetweenthe frictionsurf aces, that isto: say-between the brake 'li'ning" material and the brake drum, very accurate placement I and disposition of the brake 'liningis necessary; This: is particularly true withs the hard brake linings which have come into use in the last few years. Variations occur in the I material constituting the brake shoes, and' the brake lining stock itself may vary in thickness. Accordingly. even though a piece of brake lining be ver-y carefully placed upon a brake shoe, thee'ngaging surface may still be irregularso'as to not provide an even or uniform surface'to surfa'ce contact with the brakedrum. l

The present invention contemplates the pro vision ofca brake truing devicefor truin'g the frictional face of the brake-lining material. --The deviceis so constructed for so-trimming or truin'g the brake lining whilethe-same is in position on a brake shoe mounted upon the automotive structural "parts adjacent the wheel axle 'or spring; In other words, thebrake lining is trued insitu. I i I In the accompanying drawingsi I I Fig. l isa view illustrating the front axle'and the wheel spindle and some of the brake mecha nism of an automotive vehicle showing the tool of the presentinvention' in place; the viewshowing part of the tool in section substantially on line 1-1 of Fig. 2 and showing part of the tool including thecutter element in the position indicated by line la-1a of Fig. 2. I I Fig. 2 is a view with some parts cutaway and some parts in section looking in the direction'of the arrows 2-2 of Fig. 1. II

Fig. 3 is a view taken substantiallyon line 3-3 of Fig. 1.

Fig. 4 is a view taken substantially on line 4-4 of Fig. 2. V

The front axle of an automotive vehicle is illustrated at Lthe wheel spindle is shown at 2. the back plate of the brake structure is shown at 3, brake shoes at 4, and brake lining attached -to theshoes ati5. Some other par-ts areshown ly} applicable for use on reaI- wheels whe re; --insuch asa steeringlarm 6; atie rod 1 and'a..brake operating arm 8 swiveled as at'lli} These; parts are not shownin" anyp'ar'tic ular form-as the -in- 1 strument ofthe invention maybe used with all kinds of vehicles an'd 'the parts thus far' de? any kind of variation insofar as this invention is concerned "The tool of this invention ise'qual'f stead of a wheel spindle, a live-axle 'member-prog I jects from the axle housing for carrying the ve: hicle. T: "The-tool is advisedly 'of a simple structure and. it; comprises-a central "bearing" member 10 f de signedyto be swiveled upona wheel spindle or axle. Inasmuch as the spindles a'nd'axle's at ya- .rious'automotive vehicles vary in sizejthebearihg member ll may be placed on the spindle or axle I by j means of an adaptor bushing i 4 anda suit; able number of" such adaptor bushings may. be on hand to'a'daptlthe tool to various vehicles. 1 An adjustable adaptorbushing may beused such as the one disclosed in; application Number-436510 of "March 17; 1930;; A framlike-struct'uifejis co stituted bya'pair "of r ds] l'2- which may pass, through aperturedbosses 13' and the bearing memb'erglflj A set screw" M may be provide d' in one or 'both bosses for/ maintaining; the bearing memberin a proper-adjust djposition jvithj."

fitted; and "it rnay. fbe eguipped'with a, suitable handle20. Thejmember t9 may carry'atone' end a head 21- de signed to be received? in' a "suitable recess in a boss 22 of the bearing member H); A washer or plate 23 maybe fitted against the boss 22 so as to' overlie the head 2| and it may be secured'to the. member H! by suitable means such as screws 24-. Accordingly, it will be noted that the threaded member l9 may be rotated, and

when it is so rotated the bearing member ID and the frame are shifted relative to each other. This of course preferably is done-when the set screw I4 is loosened. A suitable gauge or other indicia device is provided. and may take the form of a disk 25 pinned or otherwise fixed to the member l9 to rotate therewith, and this disk has suitable markings, such as-for example, the indicia 26 on its periphery. These markings may be used scribed, except the brake 1ining,'are'-s'ubject to" I it I in cooperative relation to a zero indicia or mark 21 on the plate 23.

On the opposite end of the rods l2 there is disposed an electric motor 30, the stator of which may be provided with apertured lugs 3| for receiving the ends of the rods 12, and which may be fixed thereto by set screws 32. This motor may be provided with a knob or handle 33. The shaft of the-motor is illustrated at 34, and it is arranged to receive preferably detachably, a cutting or milling instrument 35 having cutting ing plungers 39 and 40. V

This tool may be used in making an initial brake assembly, in the making of a reassembly after the brake shoes have been relined, or in 'truing worn brake linings where such latter condition may exist.

In the useof the tool the internal diameter of a brake drum may be first determined, and the brake shoe maybe adjusted so as to approximate the diameter of the drum. 'Having determined the internal diameter of the ;drum, the truing toolmay be adjusted to the drum diameter so that the inner cutting edge of the tool 35 is disposed relative to theaxis of member ID a distance substantially equalto thedrum radius. This may be accomplished by turning the screw l9 to shift the member loin the frame. Once the position is properly attained .the set screw I 4 may be tightened to hold theposition.

The gauging device provided by the indicia on the washer 25- and, the zero point,21 on the plate 23 ,may be employed in varying the position of the cutting tool. The spacing of the markings on the washer 25 may be such as related to the pitch vof the screw'threads on the member I 9 that-from ,one marking to another indicates .001 of an inch. Accordingly, by noting the marklngs the cutting tool may be adjusted toward and away from the center a known distance as determined in a small unit such as .001 inch. In

making a larger adjustment involving several turns of the member J9, the user should know how manyv thousandths of an inch are represented'by one complete turn, and this may be about a hundredand twenty-five. a

The tool may now be .journaled on a wheel spindle oraxle shaft. through the means of a suitable adaptor ,bushing, and the motor started in .operation; ,The tool may be rocked on the wheel spindle. oraxle shaft causing the cutting tool 33f to shift over the brake lining material. action is preferably continued until the en tire exposed face of the brake lining has been a brake shoe and the brake drum, and the brake lining job is completed save for replacing the wheel and brake drum. The adjusting of the shoe'for proper clearances may be carried out by suitable adjusting or gauge tools. It will be appreciated that in some installations the toe and the heel of the brake shoe are adjusted for difierent clearances as regards the drum, but these are items which are independent of the present invention.

The particular tool 36 shown hereinis one of a milling cutter type, and preferably with hard brake linings it is made of high speed tool steel.

However, other types of tools may be provided such as sanding or grinding tools such as the stone illustrated in the case above referred to of which this application is a continuation in part.

We claim:

1. A tool for truing brake linings, comprising a hub member adapted to be rotatably supported on a wheel spindle or axle shaft, a pair of parallel rods carried by the hub member, a motor carried by the ends of the rods on one side of the hub member, a rotary cutting tool secured to the motor shaft and adapted to project over the adjacent brake lining material, a bracket connecting the opposite ends. of the rods, a shaft screw threaded in the bracket, means connecting the shaft to the hub element whereby the shaft may rotate relative to the hub, and means for rotating the screw threaded shaft.

2. A brake truing tool, comprising a hub element adapted to be rotatably mounted upon a wheel spindle or axle shaft, a pair of opposite apertured lugs on the hub, a pair of rods extend.- ing through the lugs and slidable therein, a motor, means attaching the motor to the ends of the rods, a rotary cutting tool connected to the motor shaft and adapted to project over the adjacent brake lining, a bracket connecting the opposite ends of the rods, a screw threaded: shaft threaded into the bracket, a handle for turning the same, means rotatably connecting the screw threaded shaft to the hub, and gauging means comprising elements provided with indicia, one fixed to the hub and one fixed to shaft. i ALVIN L. MILLER.

RUSSELL H. MILLER.

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the threaded v 

